The invention generally relates electrical chemistry and to processes and A compositions used for electrolysis. More specifically, the invention relates to electrolytic material treatment of water, sewage and other waste water. Another aspect of the invention relates to liquid purification and separation utilizing electrical or wave energy.
The separation of an aqueous solution into water and an agglomerate can be accomplished by applying a voltage across the solution. While this process is effective, it involves a series of problems that increase the complexity of the necessary equipment and increase the cost of treatment. An initial problem is that in addition to the basic separation into water and agglomerate, it is common for an electrolytic treatment involving water to produce electrolysis of the water into hydrogen and oxygen, which must be removed for safety reasons. In addition, such treatment produces a foam on top of the liquid in the electrolytic treatment chamber. This foam contains impurities and undesirable components that must be removed from the treated water. Although the foam is generated in a reaction chamber, it is allowed to remain with the treated water through a considerable portion of downstream processing, eventually being removed in a secondary separation system. Processing foam in such a downstream treatment apparatus can add substantially to the cost of treatment.
Conventional treatment systems utilize a vacuum source to remove foam. Such a vacuum source supplies high vacuum and is quite expensive in its power consumption. A substantial cost of treatment is the high vacuum system, which often uses more power than the reaction chamber itself and all of the pumps used in a typical system.
Electrodes are employed to pass a current through water. The current typically is DC or rectified AC. Suitable electrodes are formed of metal such as copper, silver, iron, or aluminum. In most applications, electrolytic treatment is considered costly both in consumption of electricity and in consumption of electrodes. A problem that substantially increases cost is hydrogen deposition on the electrodes. Hydrogen interferes with the efficient use of electricity and increases power requirements.
Electrolysis commonly is performed in a vertical up-flow reaction chamber. Vertical up-flow can be beneficial when it assists in sweeping hydrogen build-up from the electrodes and removes foam and gas from the reaction chamber. The electrodes typically are plates or blades mounted in the reaction chamber in a fixed position. The blades typically are elongated in one dimension, and the reaction chamber usually receives the blades with the elongated dimension positioned vertically. Several problems are inherent to vertical orientation. These include the substantial overhead space requirement above the reaction chamber to allow installation and removal of the blades. Another is a lateral support or bracing requirement, to support a tall, narrow reaction chamber.
The two most common techniques of mounting blades in the reaction chamber are the grooved wall and the fixed bundle. Both create a problem in that they are costly and awkward. However, the requirements of a vertical blade reaction system leave little choice.
The grooved wall is created by forming guide slots within the walls of the reaction chamber, itself. Each blade is dropped into the chamber with its vertical side edges engaged in an opposed pair of such slots. When all blades are installed, each occupies a defined position and a fixed gap separates each blade from the next. The size of gap is dictated by the spacing of the grooves in the reaction chamber wall. Likewise, the thickness of the blades is dictated by the width of the slots. While the grooved wall system is effective, it creates a problem in flexibility for different applications. The reaction chamber is not well suited to use a different size or number of blades, and the gap between blades cannot readily be altered. However, since a vertical reaction chamber tends to be quite deep and not very wide, it appears necessary to guide the blades with a structure that can be engaged at the top of the chamber. Hence, the long vertical slots are used of necessity.
The fixed bundle mounting technique employs blades assembled by bolting together the blades into a unit with spacers inserted between them. The bundle is dropped into a reaction chamber as a unit, or lifted from it, as a single unit A bundle offers an advantage in flexibility, since the number and thickness of blades can be selectively altered, as can the gap between blades by using a different spacer. The primary problem with a bundle is the bundle, itself. It tends to be heavy and difficult to manipulate. Every maintenance activity requires removing the entire bundle from the reaction chamber. Cleaning, removing, adding, or replacing a blade requires disassembly and reassembly of the entire bundle. The fixed bundle eliminates the need for long vertical slots at the expense of considerable awkwardness of another type.
It would be desirable to overcome these problems of electrolytic processing so that costs can be reduced and efficiency can be increased.
To achieve the foregoing and other objects and in accordance with the purpose of the present invention, as embodied and broadly described herein, the electrocoagulation chamber and method of this invention may comprise the following.
The objects, advantages and novel features of the invention shall be set forth in part in the description that follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by the practice of the invention. The object and the advantages of the invention may be realized and attained by means of the instrumentalities and in combinations particularly pointed out in the appended claims.
According to the invention, an electrocoagulation chamber processes a horizontally flowing stream of process liquid. The chamber is constructed of a bottom wall and opposite side walls of predetermined width. Together, they define a generally horizontal, longitudinally elongated channel, in which at least a portion of the channel has an open top. A process liquid is supplied through an inlet into a first longitudinal end of the channel. The process liquid is removed from the channel through an outlet at the opposite longitudinal end of the channel. Longitudinally elongated electrode blades of predetermined height are disposed in the channel between the inlet and outlet. The blades are longitudinally aligned with the longitudinal dimension of the channel. A disbursement chamber is in fluid communication with the portion of the channel having the open top. An air stream of positive pressure enters the disbursement chamber at a predetermined air entry location, and a cooperating negative pressure is drawn from the chamber at a predetermined air exit location. The entry location and exit location are spaced from each other in order to establish a sweeping air stream between them.
The electrocoagulation chamber may employ an adjustable baffle for controlling the flow of process liquid through the channel. The baffle is disposed between the electrode blades and the outlet and may allow flow both under and over the baffle wall. It closes the second longitudinal end of the channel to at least the height of the electrode blades in the channel, ensuring that the process liquid covers the blades.
The electrocoagulation chamber may employ at least one slotted portable blade guide. The slot is sized to receive an edge of an electrode blade. The blade guide is positioned in the reaction chamber on top of at least one of the electrode blades, and the slot in the blade guide engages a top edge of the electrode blade. The blade guide covers only a minor portion of the length of the elongated electrode blade. A second, similar portable blade guide may be positioned on the bottom of the reaction chamber and below at least one of the electrode blades, where the bottom edge of the electrode blade is engaged in the guide slot of the second blade. A blade guide may have a width approximately equal to the predetermined width of the channel, so that it will support the engaged edge of the electrode blade in a fixed position between the sides of the channel.
Another aspect of the invention provides a method of continuously processing a liquid stream flowing through an electrocoagulation chamber. The steps of the method provide an,elongated, generally horizontal electrocoagulation chamber having an open top over at least a portion of the chamber. Further, a plurality of longitudinally elongated electrode blades of a predetermined height are disposed in the chamber with their longitudinal dimension generally aligned with the longitudinal dimension of the chamber. The process liquid is continuously supplied into a first longitudinal end of the chamber for longitudinal flow through the chamber. The liquid in the chamber is continuously treated by electrocoagulation, thereby generating foam and gas byproducts. These by-products are continuously entrained in a sweeping air stream applied over the flowing liquid at the open top portion of the chamber. The air stream and entrained contents are continuously removed from the chamber at an air stream exit. The process liquid is continuously removed from the second longitudinal end of the chamber.
The method includes controlling the flow of process liquid through the chamber by interposing a baffle between the electrode blades and second end of the chamber. The baffle closes the second end of the channel to at least the predetermined height of the electrode blades within the chamber, thereby ensuring that process liquid covers the blades.